1. Field of the Invention
The present invention relates generally to spark plugs, and more specifically to a method of manufacturing a spark plug.
2. Description of the Related Art
Spark plugs are well-known in the art. A spark plug generally includes an elongated body having an electrical connector at one end. A pair of variable-spaced electrodes are typically provided at an opposing end, with one of the electrodes being electrically connected to the electrical connector.
In most conventional spark plugs, one of the electrodes includes a cylindrical post while the second electrode is generally J-shaped and has a portion which overlies one end of the cylindrical post. Consequently, upon the application of voltage to the cylindrical post, a spark is formed between the end of the cylindrical post and the overlying portion of the other J-shaped electrode. The spark is used to try to ignite fuel within the combustion chamber of an internal combustion engine.
In general, the electrical spark between the post and the other electrode will occur at the position of the shortest distance between the two electrodes. Consequently, in conventional spark plugs, the spark repeatedly strikes or extends between the same two surfaces on the two electrodes during operation of the spark plug, which has many associated disadvantages.
One disadvantage is that since the spark repeatedly strikes the same area on both electrodes, a portion of the electrode is repeatedly ablated by the spark, which can result in premature failure of the spark plug. Another disadvantage is the smolder caused by conventional J-shaped wire has a tendency to obstruct and divert the incoming air fuel charge, typically causing a lighting and quenching and relighting of the flame front.
A more serious disadvantage of conventional spark plugs is that due to ionization caused by the spark during operation of the spark plug, the spark plug may misfire during operation of the internal combustion engine due to the small surface firing area. For each misfire of the spark plug, the fuel within the combustion chamber is not ignited, but instead, exhausted to the atmosphere. This has an adverse affect not only on the efficiency of the engine, but it also causes fouling of the plugs and increases the exhaust of noxious fumes and pollutants to the atmosphere causing smog and possibly global warming. This is particularly critical in light of ever increasing governmental regulations and environmental concerns regarding the permissible level of emissions from spark-ignited internal combustion engines.
Recent spark plugs have been designed to address the aforementioned deficiencies. In particular, U.S. Pat. Nos. 5,936,332 and 6,060,822 both disclose a spark plug having a semispherical electrode and an arcuate semicircular electrode secure to the spark plug body adjacent semispherical electrode such that the semicircular electrode has its inner surface equidistantly spaced from the surface of the semispherical electrode.
However, difficulties have arisen in relation to manufacturing the spark plug, particularly in mass quantities. More specifically, the particular configuration and spacing between the semicircular electrode and the semispherical electrode has been difficult to mass produce in a timely and economical manner.
The present invention addresses and overcomes these deficiencies by providing a method of manufacturing the spark plugs which are more efficient then conventional spark plugs, and may be produced in a timely manner and at an economical cost. These and other advantages attendant to the present invention will be described in more detail below.